Field of the Invention
The present invention relates to an endoscope including an elevator that controls the derivation direction of a treatment tool, in a distal end portion of an insertion portion.
Description of the Related Art
In an endoscope, various treatment tools are inserted in a treatment tool entry port provided in an operation portion, are led out from a treatment tool exit port opened in a distal end portion and are used for treatment. For example, various treatment tools are used such as a guide wire or a contrast tube in a duodenoscope, and a puncture needle in an ultrasonic endoscope, and, additionally, a forceps and a snare in a direct-view endoscope or a side-view endoscope. In such treatment tools, it is necessary to change the derivation direction in a distal end portion to treat a desired position in a subject, and, therefore, a treatment tool elevating mechanism (forceps elevator, hereinafter referred to as “elevator”) is provided in the distal end portion.
As such a treatment tool elevating mechanism, there is known a mechanism in which an operating wire is attached to an elevator and extended to the proximal end side of an endoscope, and the elevator is rotated around a rotating shaft by performing push-pull operation on the operating wire with an operating lever provided in an operation portion so as to change the position of the elevator between a erecting position and a reclining position. Moreover, there is known a so-called lever-type mechanism in which an elevator erecting lever which is housed with an elevator across a partition wall is coupled to the elevator with a rotating shaft, an operating wire is attached to the elevator erecting lever, and the elevator is rotated around the rotating shaft by pushing and pulling the operating wire with an operating lever included in an operation portion so as to change the position of the elevator between a erecting position and a reclining position (see Japanese Patent Application Laid-Open No. 2014-046167, Japanese Patent Application Laid-Open No. 2010-201020, and Japanese Patent Application Laid-Open No. 2004-141315).
In such the treatment tool elevating mechanism, a seal member is disposed between the outer wall surface of a rotating shaft and the inner wall surface of a holding hole of a partition wall which rotatably supports this rotating shaft in order to form an airtight surface with this seal member. Thereby, blood and water, and so on, are prevented from entering from the elevator housing chamber side which houses the elevator to the erecting lever housing chamber side which houses the elevator erecting lever.